Nippon Kagaku Kaishi, p. 253, (1991) discloses a process for producing ethyl D(+)-2-[4-(6-chloro-2-quinoxalyloxy)phenoxy]propionate, which comprises reacting an alkali metal salt of 4-(6-chloro-2-quinoxalyloxy)phenol with ethyl L-2-chloropropionate. JP-A-7-278047 discloses a process for producing D(+)-2-[4-(6-chloro-2-quinoxalyloxy)phenoxy]propionic acid, which comprises reacting an alkali metal salt and/or an alkaline earth metal salt of 4-(6-chloro-2-quinozalyloxy)phenol with an alkaline earth metal salt of L-2-chloropropionic acid. Further, U.S. Pat. No. 4,687,849 discloses a process for producing 2-isopropylidene aminoxyethyl D(+)-2-[4-(6-chloro-2-quinoxalyloxy)phenoxy]propionate, which comprises reacting 2-isopropylidene aminoxyethyl L(-)-2-(p-toluenesulfonyl)oxypropionate with 4-(6-chloro-2-quinoxalyloxy)phenol, a process for producing 2-isopropylidene aminoxyethyl D(+)-2-[4-(6-chloro-2-quinoxalyloxy)phenoxy]propionate, which comprises reacting 2-isopropylidene aminoxyethyl D(+)-2-(4-hydroxyphenoxy)propionate with 2,6-dichloroquinoxaline, and a process for producing 2-isopropylidene aminoxyethyl D(+)-2-[4-(6-chloro-2-quinoxalyloxy)phenoxy]propionate, which comprises reacting D(+)-2-[4-(6-chloro-2-quinoxalyloxy)phenoxy]propionic acid chloride with 2-isopropylidene aminoxyethanol. Further, JP-B-7-25753 discloses a process for producing tetrahydrofurfuryl 2-[4-(6-chloro-2-quinoxalyloxy)phenoxy]propionate, which comprises reacting tetrahydrofurfuryl 2-bromopropionate with 2-(4-hydroxyphenoxy)-6-chloroquinoxaline, and JP-A-4-295469 discloses a process for producing 2-isopropylidene aminoxyethyl D(+)-2-[4-(6-chloro-2-quinoxalyloxy)phenoxy]propionate, which comprises an ester exchange reaction of ethyl D(+)-2-[4-(6-chloro-2-quinoxalyloxy)phenoxy]propionate obtained by a reaction of 2,6-dichloroquinoxaline with ethyl D(+)-2-(4-hydroxypheoxy)propionate.
The process disclosed in Nippon Kagaku Kaishi, p. 253 (1991) is not necessarily industrially satisfactory for producing a product of high optical purity.
Whereas, JP-A-7-278047 discloses that in the reaction of an alkali metal salt of 4-(6-chloro-2-quinoxalyloxy)phenol with an alkali metal salt of L-2-chloropropionic acid, the reaction is terminated at a conversion of about 50% due to a side-reaction, and the yield is very low. The same publication also discloses that a barium salt is particularly preferred as the alkali salt and/or the alkaline earth metal salt. However, if the barium salt is used, there is a problem that a large amount of barium-related compounds as typical by-products is formed, and it has been desired to develop a more efficient production process.